---
title: Function Apply
description: "## Method Reuse With the `apply()` method, you can write a method that can be used on different objects. --- ## The JavaScript apply() Method The `apply()` method is similar to the `call()` method (previous chapter). In this example the **fullName** method of **person** is **applied** on **person1**: ### Example `var person =…"
url: "https://apprentice.mn/docs/function-apply/"
updated: "2021-05-19"
category: Javascript
---

# Function Apply

## Method Reuse

With the `apply()` method, you can write a method that can be used on different objects.

---

## The JavaScript apply() Method

The `apply()` method is similar to the `call()` method (previous chapter).

In this example the **fullName** method of **person** is **applied** on **person1**:

### Example

      `var person = {
  fullName: function() {
    return this.firstName + " " + this.lastName;
  }
}
var person1 = {
  firstName: "Mary",
  lastName: "Doe"
}
person.fullName.apply(person1);  // Will return "Mary Doe"`

> ## The Difference Between call() and apply()
>
>
>
> The difference is:
>
>
>
> The `call()` method takes arguments **separately**.
>
>
>
> The `apply()` method takes arguments as an **array**.
>
>
>
> The apply() method is very handy if you want to use an array instead of an argument list.
>
>
>
> ---
>
>
>
> ## The apply() Method with Arguments
>
>
>
> The `apply()` method accepts arguments in an array:
>
>
>
> ### Example

    `var person = {
  fullName: function(city, country) {
    return this.firstName + " " + this.lastName + "," + city + "," + country;
  }
}
var person1 = {
  firstName:"John",
  lastName: "Doe"
}
person.fullName.apply(person1, ["Oslo", "Norway"]);`

Compared with the `call()` method:

### Example

      `var person = {
  fullName: function(city, country) {
    return this.firstName + " " + this.lastName + "," + city + "," + country;
  }
}
var person1 = {
  firstName:"John",
  lastName: "Doe"
}
person.fullName.call(person1, "Oslo", "Norway");`

## Simulate a Max Method on Arrays

You can find the largest number (in a list of numbers) using the `Math.max()` method:

### Example

      `Math.max(1,2,3);  // Will return 3`

Since JavaScript **arrays** do not have a max() method, you can apply the `Math.max()` method instead.

### Example

      `Math.max.apply(null, [1,2,3]); // Will also return 3`

The first argument (null) does not matter. It is not used in this example.

These examples will give the same result:

### Example

      `Math.max.apply(Math, [1,2,3]); // Will also return 3`

### Example

     `Math.max.apply(" ", [1,2,3]); // Will also return 3`

### Example

     `Math.max.apply(0, [1,2,3]); // Will also return 3`

## JavaScript Strict Mode

In JavaScript strict mode, if the first argument of the `apply()` method is not an object, it becomes the owner (object) of the invoked function. In “non-strict” mode, it becomes the global object.

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